OPEC sees oil demand growing by 7.3 million barrels a day through 2023 and 14.5 million bpd by 2040.

The United States will provide most of the new oil supply over the coming decade, but OPEC production will return to growth around 2025, the cartel says.

Men work for Iraqi Drilling Company at Rumaila oilfield in Basra, Iraq,

Essam Al-Sudani | Reuters

The oil industry will need to shell out about $11 trillion over the next two decades to meet the world's growing appetite for crude, OPEC says in its annual outlook.

The cost of keeping the globe fueled up assumes that OPEC's vision for the future comes to pass. In that vision, oil demand continues to grow and crude still makes up the lion's share of the energy mix, even as more electric vehicles hit the road.

OPEC has warned for years that oil producers shouldn't get complacent about investing in future production. Spending on new output fell significantly in 2015 and 2016 during an historic oil price downturn.

"While investments picked up slightly in 2017 compared to the previous two years, and the expectations are for higher levels again in 2018, it is vital that as an industry we ensure there is timely and adequate investment so as not to lead to a supply shortage in the future," OPEC Secretary General Mohammad Barkindo said in OPEC's World Oil Outlook 2018

The report forecasts global oil demand will grow by 7.3 million barrels a day between 2017 and 2023, eventually hitting 104.5 million barrels a day. By 2040, OPEC sees the world consuming nearly 112 million barrels a day.

That growth will be front-loaded. After growing by 1.6 million barrels a day through 2020, demand growth will slow to just 200,000 bpd between 2035 and 2040.

The biggest driver will be a boom in the number of vehicles on the road, especially in China, India and other parts of Asia. The world's vehicle fleet will more than double to 2.4 billion vehicles by 2040, OPEC forecasts.

By that time, OPEC thinks there will be about 320 million electric vehicles on the road, or about 13 percent of the worldwide fleet.

The United States will play a major role in meeting growing demand for petroleum over the next decade, according to OPEC.

The group forecasts U.S. output of crude oil and other liquids will grow from 14.4 million barrels a day last year to 20.2 million barrels a day in 2025. That growth will mostly come from the nation's shale fields, where drillers use advanced technology to free oil and gas from rock formations.

However, OPEC thinks American production will top out sometime in the back half of the 2020s and ultimately fall back to about 17 million barrels a day by 2040.

It's worth noting OPEC ministers incorrectly predicted in 2014 that the oil price downturn would force high-cost U.S. shale producers to shut down production. Instead, shale drillers drove down their costs and OPEC was forced to cut output to end the rout.

Strong growth from the United States, Brazil, Canada and Kazakhstan in the coming years won't leave much room for OPEC to put more barrels on the market, according to the forecast. Howeer, the cartel thinks it will start growing its output around 2025. After playing second fiddle to the United States, OPEC projects its output will grow by about 8 million barrels a day to nearly 40 million barrels a day between 2025 and 2040.

Meanwhile, the world's current top producer, Russia, will probably see its production remain flat at about 11.2 million barrels a day through 2023. That's because Russian investment will likely go towards preventing further production declines, and sanctions against Moscow will prevent the industry from investing in shale, deepwater and Arctic drilling.